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Ann Thorac Surg 1995;60:60-65
© 1995 The Society of Thoracic Surgeons
Joseph B. Whitehead Department of Surgery, Emory University School of Medicine, Atlanta, Georgia
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Abstract |
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 TopFootnotes Abstract IntroductionMaterial and MethodsResultsCommentConclusionReferences |
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Methods. The outcomes of 68 patients having coronary artery bypass grafting after stent placement were reviewed. The mean age was 60.5 ± 9.7 years, and 71% were male. Thirty-seven percent had hypertension, 13% had diabetes, 62% had class III or IV angina, 60% had multivessel disease, and 40% had sustained a prior myocardial infarction. Fifty-three patients underwent emergency operation, 22 with hemodynamic collapse immediately after percutaneous transluminal coronary angioplasty, and 7 others required urgent revascularization within 24 hours of angioplasty. Seventeen underwent coronary artery bypass grafting for acute closure of the stented vessel several days after the angioplasty procedure.
Results. There was no correlation between urgency of the procedure, previous infarction, or previous coronary artery bypass grafting with successful procedure. The in-hospital mortality was 4.4%, 21% had a Q-wave myocardial infarction, and 1.5% sustained a stroke. Ejection fraction was the only correlate of long-term mortality.
Conclusions. Coronary artery injury for which stents are placed for acute or threatened occlusion or to prevent restenosis but then fail, thus necessitating coronary artery bypass grafting, can be treated successfully. Although the rate of Q-wave myocardial infarction is substantial and related to the initial ischemic insult, the long-term survival and event rates are excellent with prompt surgical revascularization.
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Introduction |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentConclusionReferences |
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Even with the advances in interventional cardiology over the past decade, approximately 4% to 8% of cases of percutaneous transluminal coronary angioplasty (PTCA) are complicated by either acute or threatened coronary artery closure [1, 2]. The intracoronary stent was developed in an attempt (1) to provide a nonsurgical method of preserving vessel patency after disruption of the arterial lumen that can occur with angioplasty and (2) to diminish the development of restenosis [3–5].
However, even with stenting, a number of PTCA patients continue to require emergency coronary artery bypass grafting (CABG) for treatment of persistent myocardial ischemia in the acute setting or later when the stented segment thromboses. Urgent or elective CABG may also be considered indicated when a large volume of myocardium is in jeopardy distal to a stented segment. The purpose of this study is to review our initial experience in the management of patients undergoing CABG after failure of intracoronary stenting.
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Material and Methods |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentConclusionReferences |
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Acute coronary artery closure syndrome developed before, during, or after stent placement in 68 patients (15.4%) and required emergency CABG. Complete data are available on 67 patients. The mean age was 60.5 ± 9.7 years, and 48 (71%) were male. Twenty-five patients (37%) had hypertension, 9 (13%) had diabetes, and 42 (62%) had class III or IV angina. Twenty-seven patients (40%) had sustained a prior myocardial infarction (MI), and 41 patients (60%) had multivessel disease. Eight patients (12%) had undergone previous CABG. Mean ejection fraction (EF) was 0.58 ± 0.11% with 11 patients (16%) having a left ventricular EF of less than 0.50 (mean EF, 0.42 ± 0.05).
Surgical Classification
A surgical classification was assigned on the basis of the clinical instability of patients requiring CABG. Patients were divided into three major groupings (Table 1
). Those with ongoing ischemia, chest pain, hypotension, need of an intraaortic balloon pump (IABP), or impending stent or vessel thrombosis were termed emergent and were taken directly from the cardiac catheterization laboratory to the operating room. There were 53 patients (78%) who required emergency operation. Twenty-two of these patients were in shock with hemodynamic collapse and ongoing maximal resuscitation en route to the operating room. Emergency revascularization was required for 10 patients more than 24 hours after stent deployment: in 8, at 1 day to 7 days and in 2, more than 7 days after stent placement when late occlusion of the stented segment occurred.
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In summary, using these criteria, 53 patients (78%) were classified as emergent, 9 (13%) as urgent, and 6 (9%) as elective surgical patients. Fifty-one patients (75%) were operated on within 24 hours of stent placement; 15 (22%), between 1 day and 7 days afterward; and 2 (3%), more than 7 days after the original angioplasty and stenting.
Coronary Artery Segments Stented
The locations of stent deployment are shown in Table 2. Stents were placed in the left anterior descending coronary artery (LAD) in 36 patients (53%); 29 of these patients including 1 with prior CABG were classified as emergent, 4 as urgent, and 3 as elective. Within the LAD subgroup, stent placement was unsuccessful in 3 patients, and 1 patient had two adjacent (tandem) stents placed. The circumflex coronary artery system was stented in 10 patients (15%), with 5 emergent, 4 urgent, and 1 elective CABG procedures. One of these patients had had prior CABG, 1 had had an unsuccessful attempt at stenting, and 1 had received a tandem stent.
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The left main coronary artery was stented in a patient who had had prior CABG with a patent left internal mammary artery graft to the LAD. The stent to the ``protected'' left main was an attempt to salvage the circumflex coronary system. This patient required an emergency reoperation. Two patients (3%) had stents placed into prior saphenous vein bypass grafts, one in the marginal system and the other in the RCA system. The former required an elective and the latter an emergent reoperation. A total of 8 patients (12%) in this series had had prior CABG. Five of them required emergency reoperative CABG, which resulted in injury to patent left internal mammary artery grafts in 2.
Coordination of Emergency Operation
When it appeared that a patient required emergency CABG, the cardiac anesthesiologist in charge of the operating room schedule for the day was notified. This person coordinated where the patient could be accommodated and which anesthesia, surgical, nursing, and perfusion teams would be involved. An anesthesia team was dispatched to the PTCA suite to assist with resuscitation if necessary, institute monitoring, provide ventilatory support, and assist with transportation of the patient to the operating suite.
Emergency Operation Protocol and Cardioplegia
Time of ischemia remains the critical factor. Therefore, rapid induction of anesthesia and rapid institution of cardiopulmonary bypass were sought for all patients, especially those with hemodynamic compromise. Extracorporeal circulation was instituted by standard techniques, and perfusion was maintained at 2.0 to 2.4 L • min-1 • m-2. Systemic hypothermia (30° to 28°C), topical hypothermia, and cold potassium crystalloid or blood cardioplegia were used for myocardial protection. An alternative myocardial protection protocol used normothermic bypass with warm blood cardioplegia induced antegrade through the aortic root and maintained retrograde by a coronary sinus catheter [6].
Prompt revascularization of the suspected (and often obvious) ischemic zone was performed first. This usually involved placing the first vein graft to the injured vessel to deliver additional cardioplegia or oxygenated blood past the obstructed zone to the distal ischemic myocardium. After completion of all bypass grafts, the patient was allowed to rest on cardiopulmonary bypass for an interval with the heart beating but empty. This allowed time for reversal of the effects of the acute ischemia. If an IABP had been employed before the operation, it was continued at least until the first postoperative day, even if the patient's early hemodynamic recovery indicated that it was no longer needed.
Selection of Bypass Conduits
Reversed saphenous vein grafts were preferred for most patients and for virtually all patients who arrived in the operating room in ongoing shock or with myocardial ischemia. Minimizing the time necessary for revascularization and providing the ability to infuse oxygenated cardioplegia and blood through a completed vein graft into the distal circulation were clear advantages for vein grafts and were not available if an in situ internal mammary artery was used as the conduit.
The left internal mammary artery was used on the basis of our assessment of the stability of the patient arriving in the operating room. If the patient was in stable condition and if the anesthesia induction and the transition to cardiopulmonary bypass were smooth, the left internal mammary artery was taken down on bypass. As the main principle, however, is restoration of blood flow to the ischemic myocardium, patients with ongoing signs of ischemia received a saphenous vein graft to the affected territory.
Data Collection
Baseline and restudy demographic, clinical, angiographic, and procedural data, including complications, were recorded by physicians on standardized forms and entered into a computerized database. Follow-up information was obtained by telephone interviews with the patients or their referring physicians. Follow-up information included occurrence of MI since the initial PTCA, subsequent need of an additional revascularization procedure (PTCA or CABG), or death (cardiac or noncardiac related). All follow-up information was recorded on standardized forms and entered into the computerized database. In addition, all events noted on forms entered into the database from hospitalization after the initial revascularization were recorded. Follow-up was complete for 60 (92%) of the 65 survivors.
Statistical Analyses
Differences in categoric variables were analyzed by 
2, and differences in continuous variables were analyzed by Student's tests [7]. Overall survival and event-free survival were determined by the Kaplan-Meier method, and probability was expressed as the mean ± the standard error of the estimate [8]. Overall survival and event-free survival analyses were performed on the total population as well as on the subgroups. End points analyzed included (1) survival, (2) freedom from MI, (3) freedom from CABG, and (4) freedom from repeat PTCA. Comparisons of total and event-free survival were made using the Mantel-Cox method [9]. Correlates of late events were determined by the Cox proportional hazards model. For Cox model analyses, continuous covariates were not broken into groups. All statistical analyses were performed with BMDP statistical software (Los Angeles, CA).
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Results |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentConclusionReferences |
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years of this study (November 1987 to March 1994), 441 intracoronary stenting procedures were performed to support 11,039 PTCAs. Acute or threatened vessel closure developed in 68 patients (15.4%) who required CABG after failure of intracoronary artery stenting. Seventy-eight percent of the CABG procedures were done as emergencies. There was an early surgical survival rate of 95.6% (three hospital deaths, 4.4%). Mean aortic cross-clamp time was 30.4 ± 16.7 minutes. Mean cardiopulmonary bypass time was 76.2 ± 42.7 minutes. Fifty-five patients (81%) received three or fewer bypass grafts; 13 patients (19%) had left internal mammary artery–LAD grafts. There were an average of 2.5 grafts per patient. Patients with an EF of less than 0.5 had a longer hospital stay (14.4 ± 15.8 days versus 8.1 ± 3.0 days; p = 0.13).
A total of 16 patients (24%) required an IABP preoperatively with 6 more (9%) requiring intraoperative IABP support. Two patients (3%) had an IABP postoperatively. Overall, an IABP was used in 24 (35%) of 68 patients.
Periprocedural Complications
Fourteen patients (21%) sustained Q-wave MIs (Table 3). Seven of them underwent CABG within the initial 24 hours after stent placement, and the remaining 7 had CABG 1 day to 7 days after stenting. As Table 3 shows, nine (64%) of the 14 in-hospital Q-wave MIs were in patients with LAD angioplasty and stents and 4 (29%), in patients with RCA or RCA–saphenous vein graft angioplasty and stent placement. Five (36%) of the 14 Q-wave MIs developed in patients who had required urgent operation after stent deployment in the LAD.
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Hospital Deaths
There were three in-hospital deaths, an overall mortality rate of 4.4%. The first patient had undergone nontandem stenting of the proximal and middle RCA. She was taken to the operating room in extremis with full resuscitation underway and underwent emergency CABG with saphenous vein grafts to the LAD, distal RCA, and first obtuse marginal branch of the circumflex. She was weaned from cardiopulmonary bypass with excellent hemodynamic variables. Some time after protamine sulfate administration, abrupt right ventricular failure related to thrombosis of the entire RCA and right ventricular branches between the two occluded stents developed.
The second patient died of complications of an ischemic leg leading to renal failure. She had undergone emergent CABG on the same day as stent placement in the circumflex. The third patient died of sepsis after adult respiratory distress syndrome caused by cytomegalovirus pneumonia 61 days after urgent CABG. He had undergone urgent revascularization less than 24 hours after stenting of the circumflex artery.
Late Results
The actuarial survival of 60 (92%) of the 65 hospital survivors is presented in Figure 1. The overall survival rate at 6 years was 88.3%. This figure also indicates the detrimental effect of preprocedural left ventricular dysfunction as measured by reduced EF on late survival. When the preprocedural EF was 0.50 or greater, the survival rate was 93.3%, but if the EF was less than 0.50, the survival rate dropped to 73.3% (p = 0.01517). This detrimental effect of reduced preprocedural left ventricular EF on late survival proved the only correlate of long-term mortality.
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demonstrates the freedom from subsequent events and survival. There were 15 Q-wave MIs (22%) observed, all but one occurring in the periprocedural interval. The late Q-wave MI was at 61 days. Preprocedural EF had no effect on the incidence of early or late Q-wave MI. Additional coronary revascularization was required in only 1 patient (1.5%) 7 years after stenting, and additional PTCA was performed in 3 (4.5%) patients during the follow-up.
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Comment |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentConclusionReferences |
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We report our 6-year experience with surgical support of intracoronary stenting. In this series, 15% of patients undergoing stent placement for acute or threatened coronary closure after PTCA required surgical revascularization. Stent utilization may produce a 40% to 50% decline in PTCA failures requiring emergent CABG as defined in the 1985–1986 National Heart, Lung, and Blood Institute registry of periprocedural acute closures [1]. In that study, acute coronary occlusion was the single most important factor influencing mortality, MI, and requirement of emergency CABG.
Intracoronary Artery Stenting
After initial success of the intracoronary stent as a ``bridge'' to emergency CABG was demonstrated, its application has proceeded rapidly with a major goal being the avoidance of emergency CABG. Depending on the initial indication for stent placement (elective dilation versus acute closure), emergency stent deployment has been performed in between 5% and 15% of patients having coronary angioplasty in single and multicenter trials [3, 4, 11, 12]. The incidence of Q-wave MI after stent placement has been reported generally to be 5%, but this figure excludes patients having CABG [4, 5, 11, 12]. The rate of acute MI after CABG for failed stents has not been well documented.
As experience with intracoronary stent deployment has increased, cardiologists have expanded their patient selection criteria for PTCA [4]. Patients with multivessel disease and diminished EF are now undergoing PTCA with use of the stent in the event of dissection, acute closure, or suboptimal results [4, 11, 12]. Although the use of the stent as a ``safety net'' appears to be supported by the initial data from early interventional cardiology trials, the long-term benefit of this interventional technique versus surgical revascularization has not yet been documented [4, 11, 12]. The treatment of patients with more severe coronary disease by angioplasty is evident in the patient population referred for CABG after stent placement or after failed PTCA alone [13, 14].
Surgical Experience
Our data demonstrate that timely surgical revascularization is very successful in rescuing patients who experience failure of intracoronary artery stenting. This is true whether stent failure occurs immediately after a failed angioplasty or at some remote interval when late stent thrombosis develops.
Given this often critically ill patient population, the long-term survival rate of 88% with a very low incidence of late events, deaths, MI, or need of subsequent interventions is notable. The actuarial curves for late survival and freedom from late events or need of intervention are essentially flat once past immediate stent failure and surgical revascularization. These data correlate well with the excellent late results after emergency operation for failed PTCA alone [13–16].
Although the initial data on surgical ``bail-out'' of PTCA failures were generated largely from patients with single-vessel disease and good EFs in whom acute closure syndromes developed, angioplasty and stents are currently increasingly being applied in patients with multivessel disease, multiple prior PTCAs, and prior CABG [13, 14]. These expanded populations of higher-risk patients accepted for PTCA who have stents deployed will create heightened challenges when the stents fail and necessitate emergency surgical intervention. This trend has already been observed in the recent patient cohorts who require emergency operation for failed PTCA [14]. It is supported in the present series by the adverse effect of preprocedural left ventricular dysfunction on both early and late survival.
Periprocedural Myocardial Infarction
The 21% incidence of periprocedural Q-wave MI after emergency CABG after stent failure in this report is comparable to that of our earlier experience [13, 14] with emergency CABG after PTCA alone. The patients who required emergency CABG after angioplasty alone and the majority of patients having CABG after failure of stents were very similar in that they underwent emergency operation for acute ischemia after interventional measures had been attempted or used. This similar rate of infarction may reflect the fact that myocardial injury had begun with the initial vessel closure and was usually becoming well established by the time the stent could be placed and the patient taken for emergency CABG. The extra time spent to deploy the stent, especially in the early cases, and the additional bleeding encountered for stent placement may have contributed to the lessened hemodynamic stability on arrival in the operating room.
Unlike the experience with failed PTCA, however, 50% of the Q-wave MIs in this study developed in 7 (47%) of the 15 patients who had CABG 1 day to 7 days after the initial angioplasty and stent implantation in contrast to the 14% (7/51) rate in the group undergoing CABG immediately or within 24 hours of stent placement. The occurrence of late postprocedural Q-wave infarction was rarely observed in the groups requiring operation after late failed angioplasty alone [14]. When late acute failure of stents occurs, it usually results in severe ischemic injury from closure of the stented vessel that is often not fully reversible by the time emergency CABG can be accomplished.
The Q-wave infarction rate of 21% looks poor compared with the rate of 0.4% reported by Carrozza and colleagues [5]. However, all patients in that series underwent elective stenting for a suspected problem potential. The patients who required stents for emergency situations after PTCA during the same interval were excluded from the report. Their patient population is entirely different from that in the current report, yet it is interesting that even in this electively stented population, 1 patient sustained a Q-wave MI (0.4%), and 10 others (5%) experienced lesser degrees of MI.
Femoral bleeding complications are major after angioplasty with stenting in all reported series because of the large caliber of catheters required and the presumed necessity for aggressive, early full anticoagulation [2–6]. We have found that when patients with stents must have emergency CABG, it is best to leave the femoral catheter sheaths in place. They can be removed after the emergency procedure is completed and the femoral artery can be repaired directly if necessary or they can be removed later in the intensive care unit when all anticoagulation has been reversed.
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Conclusion |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentConclusionReferences |
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Footnotes |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentConclusionReferences |
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Address reprint requests to Dr Craver, The Emory Clinic, Inc, 1365 Clifton Rd, NE, Atlanta, GA 30322.
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References |
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TopFootnotesAbstractIntroductionMaterial and MethodsResultsCommentConclusionReferences |
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